COVID-related hospitalizations at low point but BA.2 subvariant drives new infections: modeling

New federal modeling released today suggests there will be an increase in COVID-19 cases in the coming weeks as the far more infectious BA.2 subvariant circulates widely.

While the number of cases is expected to rise, Canada’s chief public health officer has said the national response to this type of increased disease activity will be different now than it has been. in the past.

“We are now in a transition period, and we anticipate progress will not be linear and there will likely be more bumps along the way, including a resurgence of cases this spring,” Dr Theresa said. Tam.

“However, with higher levels of population immunity, proven protective practices to slow the spread and reduced pressure on the healthcare system, we are in a better position to get back to more of the things we love, all continuing to protect each other.”

The increase in cases was not unexpected, Tam said, given that the federal government and provinces and territories have dismantled COVID-19 restrictions and pushed forward with a lighter touch to public health measures to curb new infections.

Tam said on Friday the number of COVID-related hospitalizations and deaths was at a low level, thanks to high vaccination coverage and natural immunity to past infections.

‘Disease activity remains high’: Tam

Since January, the number of people hospitalized with the novel coronavirus has halved, to about 5,000 people nationwide on any given day. The number of reported daily deaths is also around half of what it was just two months ago, with well under 50 deaths reported each day across the country.

That could change in the coming weeks, Tam said, as there has been an increase in cases due to BA.2, an offshoot of Omicron.

A vial of the Novavax coronavirus vaccine is pictured in London, UK. Shipments of the protein-based vaccine began arriving in Canada this week. (Alastair Grant/AP Photo)

Presenting the modeling data, Tam said “disease activity remains elevated and increasing in some parts of the country” and “hospitalization trends could increase” as a result.

WATCH: Tam discusses the reasons for the resurgence of COVID-19 in parts of Canada

Tam discusses the reasons for the resurgence of COVID-19 in parts of Canada

Canada’s Chief Public Health Officer, Theresa Tam, said whenever public health measures are relaxed, a resurgence in COVID-19 cases can be expected. Tam says she encourages people to continue wearing masks to keep the pandemic under control. 1:45

Early research suggests BA.2 is five to seven times more transmissible than the original COVID-19 strain first detected in Wuhan, China, or about twice as transmissible as the Delta variant, which first struck both late 2020 and early 2021.

While BA.2 will result in more severe cases being reported, Tam said the impact on the healthcare system should be more “manageable” than with previous waves.

Tam said going forward, the likely scenario is that Canada will experience “continuous low to moderate virus transmission” with “intermittent” waves driven by new variants and reduced immunity – a more “predictable” pattern. which can probably be managed without restriction public health measures.

Planning various scenarios

However, the Public Health Agency of Canada (PHAC) is also preparing for a “worst-case scenario” in which a new variant that is much more resistant to vaccines emerges and causes widespread severe illness.

This kind of scenario would require a return to more restrictions and enhanced “personal protective practices”.

With COVID-19 testing capacity severely limited in most regions, the federal government relied on other metrics to determine the trajectory of the virus.

PHAC has a number of sites nationwide where it monitors sewage to determine transmission trends.

The results so far paint a mixed picture.

In Ottawa, for example, sewage readings suggest viral activity has never been higher. But at the Saskatchewan sites, the signals are down.

Tam said all Canadians, no matter where they live, should get their boosters or – if they’re still holding out – the first round of the COVID-19 vaccine.

Even if someone has had an infection, they should still get that third shot three months after the onset of symptoms, Tam said, because the booster dose provides much more “substantial” protection against Omicron, including BA. .2.

“There are gaps in our recall coverage,” Tam said.

According to PHAC data, only 57% of people over the age of 18 received a third dose, which is 30 percentage points less than the share of the population who received two doses.

“Any adult over 18, when eligible, get the booster now. Get the booster,” she said. “Keeping COVID-19 vaccinations up to date is one of the best ways to protect ourselves and collectively reduce the impact of future waves.”

For people reluctant to receive an mRNA vaccine like those offered by Pfizer or Moderna, Tam said, there is the Novavax product, a protein-based vaccine that will soon be available in Canada. On Thursday, the federal government began receiving some of the 3.2 million doses it ordered from the Maryland-based company and distribution to provinces and territories is now underway.

The numbers of hospitalizations reveal how unvaccinated people are more likely to have serious consequences.

Fully vaccinated people with a booster dose were ten times less likely to be hospitalized than unvaccinated people.

People vaccinated with just two doses were also less likely to need medical attention – their hospitalization rate was four times lower than that of unvaccinated people between mid-February and mid-March, according to data from the ‘PHAC.